Very nice! Also, here is a list I have had bookmarked for about a week or so. Many of the engines are on that list since many are on Github (your list also has quite a few not on this list), but some are also separate and not listed on GH.

There are TONS of things JS can do for you. It becomes clear what it can do, and why JS is so important to web development, once you really learn PHP and learn its server-side limitations. Client-side timers, graphical effects, dynamic maps, real-time combat, etc. These are the things JS can do for your project!